R: Count the number of matches in a string.

str_count {stringr}

R Documentation

Count the number of matches in a string.

Description

Vectorised over string and pattern.

Usage

str_count(string, pattern = "")

Arguments

string

Input vector. Either a character vector, or something coercible to one.

pattern

Pattern to look for.

The default interpretation is a regular expression, as described in stringi::stringi-search-regex. Control options with regex().

Match a fixed string (i.e. by comparing only bytes), using fixed(). This is fast, but approximate. Generally, for matching human text, you'll want coll() which respects character matching rules for the specified locale.

Match character, word, line and sentence boundaries with boundary(). An empty pattern, "", is equivalent to boundary("character").

Value

An integer vector.

Examples

fruit <- c("apple", "banana", "pear", "pineapple")
str_count(fruit, "a")
str_count(fruit, "p")
str_count(fruit, "e")
str_count(fruit, c("a", "b", "p", "p"))

str_count(c("a.", "...", ".a.a"), ".")
str_count(c("a.", "...", ".a.a"), fixed("."))